Identification of Rhizoctonia solani associated with soybean in Brazil by rDNA-ITS sequences
Carregando...
Data
2003-08-01
Autores
Fenille, Roseli C.
Ciampi, Maísa B. [UNESP]
Kuramae, Eiko E.
Souza, Nilton L. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Fitopatologia
Resumo
O objetivo deste estudo foi identificar, através da seqüência de nucleotídeos das regiões ITS-5.8S do rDNA, isolados de Rhizoctonia solani causadores de podridão de hipocótilos e de queima foliar em soja (Glycine max), no Brasil. A seqüência do gene 5.8S do rDNA (155 bp) foi altamente conservada entre todos os isolados, mas foram observadas diferenças no tamanho e na seqüência de nucleotídeos nas regiões ITS1 e ITS2 entre os isolados obtidos de soja e os padrões de grupos de anastomose (AGs). A similaridade na seqüência de nucleotídeos entre os isolados do AG-1 IA, causadores de queima foliar, foi 95,1-100% na região ITS1 e 98,5-100% na região ITS2. A similaridade na seqüência de nucleotídeos entre os subgrupos IA, IB e IC variaram de 84,3 a 89% no ITS1 e de 93,3 a 95,6% no ITS2. Entre os isolados obtidos de soja pertencentes ao AG-4 e o padrão AG-4 HGI foram observadas 99,1% e 99,3-100% de similaridades para ITS1 e ITS2, respectivamente. Foi possível confirmar através da análise das regiões ITS-5.8S do rDNA que os isolados de R. solani brasileiros, causadores de queima foliar são pertencentes ao AG-1 IA e que, os isolados causadores de podridão de hipocótilos pertencem ao AG-4 HGI. A análise das regiões ITS-5.8S do rDNA não foi determinante na identificação do isolado AG-2-2 IIIB obtido de soja.
The aim of this study was to identify isolates of Rhizoctonia solani causing hypocotyl rot and foliar blight in soybean (Glycine max) in Brazil by the nucleotide sequences of ITS-5.8S regions of rDNA. The 5.8S rDNA gene sequence (155 bp) was highly conserved among all isolates but differences in length and nucleotide sequence of the ITS1 and ITS2 regions were observed between soybean isolates and AG testers. The similarity of the nucleotide sequence among AG-1 IA isolates, causing foliar blight, was 95.1-100% and 98.5-100% in the ITS1 and ITS2 regions, respectively. The nucleotide sequence similarity among subgroups IA, IB and IC ranged from 84.3 to 89% in ITS1 and from 93.3 to 95.6% in ITS2. Nucleotide sequence similarity of 99.1% and 99.3-100% for ITS1 and ITS2, respectively, was observed between AG-4 soybean isolates causing hypocotyl rots and the AG-4 HGI tester. The similarity of the nucleotide sequence of the ITS-5.8S rDNA region confirmed that the R. solani Brazilian isolates causing foliar blight are AG-1 IA and isolates causing hypocotyl rot symptoms are AG-4 HGI. The ITS-5.8S rDNA sequence was not determinant for the identification of the AG-2-2 IIIB R. solani soybean isolate.
The aim of this study was to identify isolates of Rhizoctonia solani causing hypocotyl rot and foliar blight in soybean (Glycine max) in Brazil by the nucleotide sequences of ITS-5.8S regions of rDNA. The 5.8S rDNA gene sequence (155 bp) was highly conserved among all isolates but differences in length and nucleotide sequence of the ITS1 and ITS2 regions were observed between soybean isolates and AG testers. The similarity of the nucleotide sequence among AG-1 IA isolates, causing foliar blight, was 95.1-100% and 98.5-100% in the ITS1 and ITS2 regions, respectively. The nucleotide sequence similarity among subgroups IA, IB and IC ranged from 84.3 to 89% in ITS1 and from 93.3 to 95.6% in ITS2. Nucleotide sequence similarity of 99.1% and 99.3-100% for ITS1 and ITS2, respectively, was observed between AG-4 soybean isolates causing hypocotyl rots and the AG-4 HGI tester. The similarity of the nucleotide sequence of the ITS-5.8S rDNA region confirmed that the R. solani Brazilian isolates causing foliar blight are AG-1 IA and isolates causing hypocotyl rot symptoms are AG-4 HGI. The ITS-5.8S rDNA sequence was not determinant for the identification of the AG-2-2 IIIB R. solani soybean isolate.
Descrição
Palavras-chave
anastomosis groups, foliar blight, hypocotyl rot, Glycine max
Como citar
Fitopatologia Brasileira. Sociedade Brasileira de Fitopatologia, v. 28, n. 4, p. 413-419, 2003.